<?php

declare(strict_types=1);

namespace App\Service;

final class TimeRangeResolver
{
    private const DATE_FORMAT = 'Y/m/d';

    public function __construct(private readonly string $timezone = 'Asia/Shanghai')
    {
    }

    public function resolve(?string $date, ?string $timePreset, ?string $startDate, ?string $endDate): string
    {
        if ($this->filled($date)) {
            return $date;
        }

        $now = new \DateTimeImmutable('now', new \DateTimeZone($this->timezone));
        $preset = $this->filled($timePreset) ? $timePreset : 'today';

        [$start, $end] = match ($preset) {
            'today' => [$now, $now],
            'yesterday' => [$now->modify('-1 day'), $now->modify('-1 day')],
            'last_7_days' => [$now->modify('-6 days'), $now],
            'last_30_days' => [$now->modify('-29 days'), $now],
            'this_week' => [$now->modify('monday this week'), $now],
            'last_week' => [$now->modify('monday last week'), $now->modify('sunday last week')],
            'this_month' => [$now->modify('first day of this month'), $now],
            'last_month' => [$now->modify('first day of last month'), $now->modify('last day of last month')],
            'custom' => [$this->parseDate($startDate), $this->parseDate($endDate)],
            default => throw new \InvalidArgumentException('Unsupported timePreset: ' . $preset),
        };

        if ($start > $end) {
            throw new \InvalidArgumentException('startDate cannot be later than endDate.');
        }

        return $start->format(self::DATE_FORMAT) . '-' . $end->format(self::DATE_FORMAT);
    }

    private function parseDate(?string $date): \DateTimeImmutable
    {
        if (!$this->filled($date)) {
            throw new \InvalidArgumentException('startDate and endDate are required when timePreset is custom.');
        }

        $normalized = str_replace('/', '-', $date);
        $parsed = \DateTimeImmutable::createFromFormat('!Y-m-d', $normalized, new \DateTimeZone($this->timezone));

        if (!$parsed instanceof \DateTimeImmutable) {
            throw new \InvalidArgumentException('Invalid date format, expected YYYY-MM-DD.');
        }

        return $parsed;
    }

    private function filled(?string $value): bool
    {
        return $value !== null && trim($value) !== '';
    }
}